Executive Summary
During the period 15 May to 6 August, 2016, nest boxes located at eight different lakes on the Kodiak road system and Karluk Lake on the Kodiak National Wildlife Refuge were checked by the author(s). Aurel Lake nest box AL-1 had the door blown off and Karluk Lake box KL-17 tree blew down reducing the total number of project boxes available in 2016 to 45.
Occupancy rate of available project nest boxes used by Barrow’s goldeneye (Bucephala islandica) hens was 38% (17 of 45 boxes) in 2016, matching 2015 and higher than the previous 5-year average of 31% occupancy. Three of the Buskin Lake nest boxes moved in 2015, were successfully used by common mergansers (Mergus mergus) during the 2016 nesting season, increasing the total 2016 nesting waterfowl project nest box occupancy rate 44%.
The 2016 estimated average clutch size of 9.3 eggs (range 1-18 eggs) that occurred in the 17 occupied project goldeneye boxes was a substantial increase from the previous 5-year annual average of 6.9 eggs per clutch from 2011 to 2015. Box KL-6 hatched out a project record 18 egg clutch. Similar to 2014 and 2015, unhatched eggs (N=21) were found in 4 project nest boxes during 2016. Nest boxes, NL-1 and KL-18 contained only unhatched eggs with non-incubated clutches of 1 and 17, respectively. The 2016 estimated hatching success of 80% from known outcome nest boxes (N=14) was higher than the 76% in 2015 and slightly lower than the previous 5-year project mean hatching success of 85%.
Capture and banding of goldeneye hens using project nest boxes continued in 2016 with 7 Barrow's goldeneye hens and 3 common merganser hens captured and banded during the 2016 nesting season.
The Kodiak nest box project was initiated in the spring of 2010 in an attempt to provide additional goldeneye nesting habitat and collect basic nesting ecology information. To date, over 550 Barrow's goldeneye young have been hatched from project nest boxes.